Hydraulic classifier



Apr. 10, 1923. ASL? R. B. ELDER HYDRAULIC cLAssIFIER Filed Dec, 6, 1918 5 sheets-sheet l WIT/VESSES br. TOTWS.

R. B. ELDER HYDRAULI C CLASS IYFIER Filed Dec, 6, 191B' 5 sheets-sheet 2 WIr/M8858 Apr. l0, 1923i.

R. B. ELDER HYDRAULIC CLASSIFIER 6, 1918 3 sheets-sheet 3 Filed Dec.

A ITam/E ys y construction of valve.

Patented Ahpr. .10, 1923.

UNlED A ROBERT BAXTER ELDER,

0F DENVER, COLORADOASSIGNOR TO ANDREW DARWIN ELDER, 0F DENVER, COLORADO.

HYDRAULIC CLASSIFIER.

Application filed December G, 1918. Serial No. 265,614.

To all whom t may concer/n:

Be it known that I, ROBERT BAXTER ELDER, a citizen of-the United States, anda resident of Denver, in the county of Denverfand State of Colorado, have invented certain new and useful Improvements fn Hydraulic Classifiers, of which the following is a' specification.

My invention is an improvement in hydraulic classifiers, and has for its object to provide a new and novel form of throttle valve or gate especially designed for use with hindered settling ore classifiers, for controlling the discharge of pulp from the teeter chambers of such classifiers, wherein the discharge of the heavy classified pulp from the teeter chamber is regulated by a mechanical valve which opens and closes in response to the changing of the density of the pulp in the4 teeter chamber, to maintain the thickness rand density of the pulp-bed constant or nearly so.

A further object of the invention is to provide a throttle valve or gate of the chart acter specified for giving accurate and delicate control of the outflow of liquid material from -the container, controlled by the change of the density of the liquid.

A further object of the invention is to provide a means whereby unclassified ypulp may be fed into a teeter chamber in such a manner` as lto avoid any violent agitation caused by the stream of pulp entering the teeter chamber.

ln'the drawings:

Figure 1 is a side view of a two chamhered classifier provided with the improved valve;

Figure 2 Figure 1;

Figure 3 is an enlarged view `of the valve, partly in section;

Figures 4 and 5 are .sections on the lines 4-4 and 5,-5, respectively, of Figure .'3,

' each view lookinginthe Vdirection of the arrow adjacent to the line;' v l y Figure 6 is a vertical section of a 4cone classifier provided withlthe improved valve;

Figure 7 is a sectional view of a modified ln the embodiment of the invention shown in Figures 1 and 2, a casing is provided, hav- -ing two teeter chambers 1,the said chambers being separated by a vertical partition 2 of lflows through ak screen is a section on the line yQ--Qpfp tained over the teeter chamber area. The

a partition 15 thin material, and of lesser height than the height of the teeter chambers. Each. teeter chamber is provided with a float chamber 3, supported bya vertical pipe 4, which istattached at its lower'end to the bottom 7 of the teeter chamber, and each float chamber has therein a loat 5, to which is attached the valve to be described.

Below each teeter chamber is a hydraulic chamber 6 communicating with the teeter chamber by restricted openings in the par tition or plate 7 which separates the teeterv chamber from the hydraulic chamber, form-` ing the bottom of the teeter chamber and the top of the hydraulic chamber. A casing 8 within the hydraulic chamber` forms a communication between 'the lower end of the pipe 4 and the spigot 9 which extends through the bottom of the hydraulic chamber.

above and at one side ofthe casing, by means of spigots 1Q which deliver into chambers 13 arranged below the spigots and at one side of the teeter and hydraulic chambers. Before entering the spigots l2 the feed water 11, and from the chambers 13 the water flows into thefhydraulic chambers through openings 14 in the partition wall between the hydraulic chambers and the chambers 13.V From theihydraulic chambers thewater flows through the restricted openings in the plates 7 into the teeter chambers, where it performs the work ofz classification. The openings through the partition 7 are so restricted that they. form a resistance, tothe passage of the water such that its 'even distribution is mainfeedw'ater .chamber 10 has an overflow above "neurone end, and a discharge or waste pipe 16 leads from the space formed between the partition 15 and the adjacent end of the casing.l In operation, water is supplied to the 1 chamber 1() slightly in excess of that which will flow through the spigots 12, the excess overflowing at the point. 15 and running to waste through the pipe 16. This maintains practically uniform the pressure onthe spigots 12,' and hence vthe flow of water through the spigots is uniform. The 4chambers 13 are of such height above the level Water is supplied to both teeter chambers from a feed water chamber 10 arranged adjacent to the partition 18 and of the pulp in the teeter chambers that they can support a column of water of sufiicient height to force the water to flow into the teeter chambers against any column of pulp which cantorm therein. This insures that cach teeter chamber receives. water at a uniform constant rate, which depends only on the size of the spigots 12 and on the head of water in the feed water chamber 10, and is not affected by thedensity of thel bed in the teeter chamber.

The unclassified pulp is fed into the pulp feed chamber 17, and between this chamber 17 and the first teeter c hamber is the partition 18 which is provided with numerous small perforations or openings 19 through which the pulp may pass from the feed chamber 17 into the first teeter chamber 1. A hydraulic chamber 20 is provided below that portion of the chamber 1.7 next to the partition 18, and the chamber 20 is separated from the chamber 17 by a partition 21 having openings or perforations 22 which provide a communication between the chambers 20 and 17. Water is admitted to the chamber 2O from a spigot 23, similar to the spigots 12 and leading from the chamber 10.

The water flows into a chamber similar to the chamber 13, and through an opening similar to the opening' 14 into the hydraulic chamber 20, and from this chamber through the openings 22 into the chamber 17. The openings 22 are so restricted that they form enough resistance to the passage of the water that this resistancemaintains-the distribution of the water to all of the openings 22. The water entering the chamber 17 maintains in a liquid condi-tion that portion of the pulp thus prevents the orifices 19 from becoming blocked, n'iaintaining so a` constant flow of pulp from each of these orifices. This gives a feed of' pulp to the first teeter chamber in many small streams, instead of' in one large stream, and so prevents the agitation in the teeter chamber which a` large stream would produce and which would interfere with the proper classifying action.

Those particles of' orel which are able to sink into the pulp bed in the first teeter chamber settle into this chamber, crowding out the lighter particles. The heavy parti cles are discharged from the spigot of the first teeter chamber, and the particles which cannot sink into the first teeter chamber pass over the partition 2 into the second teeter chamber, wherethe heaviest of them are again sorted out and pass into the pulp bed and through the spigot, while the lightest particles, rejected by thle second teeter chamber, pass over the partition 24 and through the pipe 25.

Each teeter chamber is provided with an -openlng 26, which is filled with some transparent material, as for instance', a sheet of through glass, so that a section of the pulp bed may be observed. Each-hydraulic chamber is provided with drain plugs 41 which may be removed to drain these chambers.

In Figures 3. 4 and 5 is shown the valve and its mounting. The said valve is a tube open at both ends and end to the float 5, so that the valve and float together form one integral structure. This structure is arranged inside of and concentric with the pipe 4 and the float chamber 3, the pipe 4 being secured to the bottom of the lteeter chamber to stand vertically in the said chamber, and being of such the plate 7 upwardly, and spacing pins 32.

extend radially from' the valve, engaging at their free ends the interior of the pipe 4, to properly space the valve 3() from the said pipe, the pins having threaded engagement with the valve. Thus the valve is always held accurately concentric with the pipe 4. The valve seat 33, which is seated loosely in a depression in 8, is a frustum 4of a cal bore. lts axis coincides with the axes ot' the valve and the pipe 4, and the upper or smaller end 'of' the valveseat is smaller than the bore ofthe valve 30, so that when the valve 30 is lowered to contact with the conical periphery of the seat, the inner edge of the lower end of the valve will make such contact. The bore of the seat connects directly a spigot 9 opens from the bore 34 throu `h the bottom of the hydraulic chamber. T 1e relation between the length of' the valve 30 and the pipe 4 is such tha-t when the pipe 30 is moved downward its lower end will touch the seat before the float 5 contacts with the float chamber 3, and the pins 32'are so placed that they will be slightly above the openings31 when the valve is closed. It will be seen that when the valve 30 lis, raised any liquid in the teeter chamber will fiow the openings 31, between the lower end of the valve and the upper end of the seat. through the bore of the seat and that of the casing 8 and out through the spigot 9. When the valve is closed, thatis` when the valve contacts with the seat. there will be an unobstructed passage through the classifier from thespi'got 9'to the space above` suspension by an up# ward moving current of water. This pulp reacts as if it were a liquid having a specific gravity greater than that of water. llVhen the class'ier is operating, the pipe 4 is immerse'd in the pulp and the annular space attached at its upper with the bore 34 of the casing 8, andl by pulp consisting of between' the pipes 4 and 30 is open to the pulp at the top of the .openings 31. The current of water moving upward through the teeter chamber maintains the pulp particles in suspension outside of the pipe 4, but in the annular space between the valve and the pipe 4 there is no upward current, so that any ore particles in this space will soon settle out, leaving clear water.` The result is that the water rises in this space until its hydrostatic pressure at the upper end of the open'- ings 31 is great enough to balance the hydrostatic pressure at this point .caused by the column of pulp outside of the'pipe 4, and

'since the water inthe annular space is a lighter liquid than the pulp it will rise, to a height above the level of the pulp in the teeter chamber.

When this column of water rises inside the pipe 4 into the float chamber 3,-the float 5 becomes a partially submerged body and it is evident that, given the proper proportioning of the apparatus, a point will be reached where the weight of the water displaced by the float 5 will equal the weight of the said float and the valve. Any further rising of the column of water will then lift the float and valve, which will open the.

valve, and permit the pulp to flow from the teeter chamber out through the spigot 9. If the pulp is being, fed steadilyto the teeter chamber the float will rise until a point is reached at which the pulp is discharged through the spigot asfast as the pulp bed is formed, and there will be maintained in the teeter chamber a bed of pulp of sutiicient thickness and ldensity to balance the column of water which lifts theloat far enough to discharge the pulp at this rate.

With the valve in closed position, er end of the valve is exposed to the hydraulic pressure due to the column of pulp in the teeter chamber, and this pressure exerts a force on the lower end of the valve, tending to lift the valve. The vertical components of any pressure on the lower end of the valve by the valve being slightly open, as in the open position 'shown in Figure 3 the samehorizontalarea is exposed to the hydraulic pressure as when the valve is shut. This would not be true if the valve were a flat disk attached to the float by a solid rod instead of by a pipe. y n such case, with the valve in the closed position, the centerof the disk would be subject only to the atmospheric pressure communicated through the spigot 9', and when the valve were slightly open, the hydraulic pressure begin to be communicated to this center of the disk.

The pressure applied to this disk would be a vertical force tending to lift the valve, and its effect would be accelerated with the opening of the valve so that when the valve 5 started to open it would open wide suddenly.

the lowl are in no material degree altered On closing, the reverse of this action would take place, causing the valve to close suddenly and the 'result' would bea periodic opening and Vclosnig 'of the valve, giving a periodic instead of a continuous discharge '-of the pulp. .Also if the valve vwere not open to the atmosphere throughout the bore thereof a partial vacuum. might be x formed inside of the same under some conditions, because of the pulp catching bubbles' of ail and carrying them downwardly through the passage 34 and the spigot 9.

Inorder that the raising and lowering of the valve 30 may be perfectly controlled by i the Hoat 5 without this control being interfered with, by the pressure or ow'o'f liquid atthe lower end of the pipe 30 three conditions must obtain: first, at the lower end of the valve any-surface 'of it except the vertical surface must be equally exposed to the hydraulic pressure with the valve opened or closed; second, the area of the surface not vertical and so exposed must be small, so that vertical forces caused by the inertia of the moving liquid impinging on this surface should not be great (that is, the walls of the valve 30-should not b e too thick); and,

third, the valvemust be so constructed thatl through the valve 'doesnotaffect vthe pressure at the upper'ven'dsof these openings, since the pressure at this point controls the height of the column of water in the float chamber 3 and hence the discharge of the pulp. With the openings 31 too short or otherwise too constricted, the pressure at the bottom of the annular space between the pipe 4 and the valve v30 is increased by the inertia ofthe mass of pulp approaching the openings 31 when the flow is in progress,and thisv interferes the valve' lby aifecting the height of the column Iof water in the chamber 3 and' gives a periodic'instead of a continuous discharge.

The bottoms of the float 5 and-of the fioatl chamber 3 are made conical, the slope of the cone 'being downward toward the center and at an angle of approximately forty-five degrees.l This is to avoid corners in which loose particles of sand or other material may accumulate. The critical'angle of a pile of sand is lessthan forty-five degrees, its way into either. the float chamber 3` or the float 5 will not be able -to'lodge there, but will pass downward, either into the teeterchamber through the openings 31 'or out-throu h the spigot 9, as the case may be.

The va ve 30'is threaded intol the lower end of the float 5, and a lock nut 36 is provided for locking the valve to the float. The lower end of the pipe 4 has threaded enwith the proper control ofy so that any particle of sand inding i and of lthe pulpin the .35,

gagement with the enlarged upper-end of the casi-ng '8, the said pipebeing threaded into the recess or depression for the seat 33. If 'the valfe 3() is lowered with respect to the float 5` a higher column of Water is required in the chamber 3 to open the valve. To support this higher column of water requires a heavier bed of pulp in the teeter chamber, so that the adjustment of the length of the valve 30 in its relation to the float 5 may be used to produce a lighter or heavier bed of pulp in the teeter chamber. This same adjustment could be made by using Weights in the float 5, the weights to be of such a shape that they would not prevent the passage of air from the float to fthefinterior of the valve 30. 1 believe that the plan of making vthe valve 3 0 adjustable in. its relation to the float 5 is to be preferred, as this adjustment is less easily tampered with.

The Wearing parts of the apparatus are the upper end of the cone shaped valve seat 33 and to a lesser extent the lower end of the pipe 30. The vseat 33 fits close enough in thedepression in the upper end of the casing 8 to be held properly centered, but to permit its removal when worn.

The relative elevation of the liquid surfaces when the classifier is operating are indicated by the dotted lines. The surface of j the pulp in the teeter chamber is indicated at w, of the water in the float chamber 3 at of the Water in the chamber 13 at valve 30 at e. The level to which the pulp rises in the valve 30 Will be determined by the size of the opening through the seat 33, in its relation to the amount of pulp to 'be discharged. This bore or opening must be large enough to discharge the required amount of pulp when the pulp is running under a pressure head less thanythat required to raise the pulp into the float 5.

.In the embodiment 4of the invention shown in Figure 6v the unclassified pulpis supplied from the' ulp launder 50 and flo-ws first into the vpulp feed chamber 51. This chamber 51 communicates with the main body ofthe classifier by an opening v52 in its bottom, and the said chamber is placed partly submerged in the liquid in the classifier so that it is partly filled with pulp at :all times. The plunging current of pulp being'fed to the classifier exhausts its force in producing agi-- tation inthe pulp chamber 51, and the pulp settles quietly through the opening 52 and forms no eddying current in the pulp in the ,classifier which might interfere with the proper action of the classifier.

he heavy ore particles settle into the casing 53 which forms the teeter chamber, and here they are held in a condition of hindered settling` by Water which comes into the teeter chamber'through the restricted openings in ther plate 54 arranged between the teeter chamber and forming the bottom thereof, and a hydraulic chamber 55 ofbwhich 1t forms the top. The water is supplled by the pipe 56 which is controlled-by a valve 57. A chamber 58 corresponding to the cham-ber 10 ofFigure 1 receives the water from the pipe 56 and supplies it to a pipe 60.l From the pipe 60 the Water passes into the hydraulic. chamber 55, the pipe 60 havmg the same function as the chambers 13 'of Figure 2. 'The chamber 58 is provided with an overflow 59 and the chamber 60 is provided wlth an overflow 61. From the overflow 50 will flow the slight excess of water supplied to it from the pipe 56 over and above that which will flow from the chamber 58 at the pressure head maintained thereon, and thls maintains a constant uniform flow of Water from the chamber 58. The overflow 61 of` the pipe 60 is above the float chamber ofthe valve, and is arranged so that any water overflowing at the overflow 61 will be admitted into the float chamber outside of the float. The overflow 61 is at a height above that to which the water in the pipe 60 will rise to create pressure eno-ugh 'in the hy* draulic chamber 55 to force the water into the teeter chamber against the regular bed of pulp which it is desired to maintain in the teeter chamber, so that under regular operating conditions the water in the pipe 60 does not overflow but stands at the level v. The float chamber 62 is similar to the chamber 3 of Figure. 1, being supported on the vertical pipe 65 corresponding to t-he pipe 4 and having openings 66 similar to the openings 31. The valve 67 has connected at the upper end thereof the float 63 similar in all respects to the float 5 of Figure 1. The valve 67 has the centering lugs similar to the. lugs 32 and co-operates at its lower end with ya seat 69 similar to the seat 33. The construction and operation of this valveare precisely the same as of that shown in Figures 1 to 5, and the .seat 69` is supported by a casing 70 corresponding to the casing 8 of Figure l.

1n operation, the water rises in lar space between the valve 67 and the pipe 65, unt1l it is high enough in the float chamber to raise the' float and the valve, which permits the pulp to flow from the teeter chamber through the bore of the valve seat and out through the casing 70. llVit-h the exception of the arrangement of the overflow 61 of the the annufeeding the pulp to the classifier, the classifier of Figure 6 operates 1n a manner identical with that of Figure 1. The overflow 6l leading to the chamber 62 1s provided e an aid in establishing the normal operating conditions when the classifier is first filled with pulp..

Suppose the classifier te be empty, and Water through the valve 57 and pulp through the launder 50 be simultaneously admitted. The pulp being the natural product rof crushed ore, contains material as fine asthe very finest slime, and as the pulplevel rises and the classifier is filled with pulp, theannular space between the pipe 65 andjthe valve 67 is filledwith water forced into fit from the vteeter chamber through the opening 66. The larger particles ofore will immediately settle out of 'this space or will not be carried up into itat all, Some smaller particles will be carried u into this space by the rising water and t e result will be that the annular space between the pipes as well as the float chamber 62 will become filled with muddy water.;v

This is a light pulp, that is, a liquid whose specific gravity is somewhere between that of the pulp in the teeter chamber and that of clear water. Therefore, it `rises'to a less height in the float chamber than acolumn of clear water would rise, in order to bal-v ance apulp bed of a given density. Hence results that the bed of pulpvmust accumulate to a density in excess of that-which it is desired to maintain regularly, before the column of muddy waterv rises highenough to lift the fioatand permit the pulp to discharge.

The increase in density of the pulp bed forces the water to. rise in the pipe 60 to a higher level than itl rises when the pulp'bed is of a normal thickness. By arranging the overfiow 61 as shown, slightly above the level c at which the water normally stands, a slight increase in density of the pulp bed raises thel level of the water in the pipe 60 until some of it overflows at 61 into the chamber 62. This furnishes clear water in the chamber 62 which displaces downwardly the muddy water and so substitutes a column of clear water for water. The column of clear water holds a level high enough to lift the float mits the pulp to fiow from the teeter chamber until the normal thickness of the pulp bed is reached and the water in the pipe 60 will thenv return to its normal level at fu'. Without this arrangement some time would elapse4 before the very fine ore particles settled from the chamber 62 and the annular space between the pipe 65 and the valve and normal operating conditions `were established. i

The overflow from the cone classifier takes place at the top of the rino- 71 which is arranged within the hopper s aped upper portion 53a of the casing. The space 72 outside of the ring constitutes a launder about the top of the classifier which conducts the overfiow to the discharge launder 73. Plugs 74 are provided inv the bottom of the hydraulic chamber for draining the said chamber. It is obvious that although but one use of this form of valve is indicated, namely,

the column of muddy which perto regulate the discharge of classified pulp from an ore classifier, restricted to Athis' specific application. y `lnthe design ofbothFigures 1,A nd G ,the float which controls'the movement ofthe its usefulness is not v throttle valve issupportedon La column of water balanced hydraulically against a poltion ofthe column yof lpulp inthe yteeter chamber. f It is theoretically possible to ob taii lthe. same control ofv the movement o the valve by the use of`a float immersedvdgirectly `in the pulp. .When the pulp becomes 'dense the force tending to lift the float `will becorrespondingly increased, sincethe yfioat isrbuoyed up by. a force edual vto the,` y,weight of thel liquid it displaces. depending on Ha lfloat immersed directly fin the pulp would not bea yd eparturefrom lthe spirit lofrmy invention. i

Figure 7 shows a construction wherein the spacin pins 32aare attached to thepipe 4 instea ,ofto they valve. The advantage of the construction shown `1n Figure 7 is'that with this construction the pipes 4" and y30 may be` keptmore accurately 'centered than A` construction v ith the yconstruction indicated inflfigure 3,

The advantage of the construction shown in Figure 3 is that with thisconstruction it is not necessary to remove the pipe 4 from its position in the teeterichamber inorder to remove the valve seat 33 when itlbecomes worn, and replace with a new valve seat.

Iclaim:` l l. In a classifier having an'outlet for the discharge of pulp, vmeans for varying the capacity of the outlet controlled by the 4density rofthe pulp, saidmeans comprising a gate or valve, afloatfor operating the gate or valveand balanced between a column of water and a column vof pulp in the container, said valve being a hollow cylindrical body vertical or, nearly so, open at top and bottom, integrally connected with the float and of smaller cross section than the' float.:

2. In .a classifier, vhaving )an outlet for the discharge of pulp, means forvarying the capacity. of the outlet controlled by the densityof the pulp, said. means comprising v a gate or valve, a fioat for operating the gate or valve and balanced ybetween a 'columnof water and a column of ulp in the container, said fioat and valve ing hollow bodies open at top and bottom, the float being of reater diameter than the valve and having its under surface tapering toward the valve. 3.1n a classifier having an outlet for the discharge of pulp, means forgvarying the capacity ofthe outlet controlled `by the density of the pulp, gate or valve, a float for operating the gate or valve and balanced between 'a column of Water and a .column of `pulp .in the container, said valve being a tubular body with thin Walle, open at top and l)ottone its Seat having ite peripheral Surface tapering toward the valve, lSide of and eoncentricallv with the valve ,and having at ite upper end a ,float chamber and having openings at ite lower end ,5, A valve ofthe character Specified .inthe Shape of a t'uhev connectin at its upper'end with a doet, the bore o'. the valve being open through the float, a valve seat with which the valve cofoperatee at ite lovver end, the valve Seat being of euch .a shape that the Ylower endolc the walls of the tuy e exposed to the hydraulic pressure with the Yvalve either open" or cloeedf 6e Meane dependiny on the densitycf'ore pulp in e container Ior regulating the dieuha'rge of. the pulp therefrom, eaid means l.consteting ,of fa" throttle valve or gate Suepeuded from a float which le supported 'on efe a column of water balanced hyd'raulicallv against all or part ofthe column of pulp in the A.contatener- 7. Means depending on the density of ore pulp in a container for regulating the discharge of the pulp therefrom, said means .consisting of a throttle valve or gate euepended from and integral with a oat Which s supported on a column of water balanced 'hydia'ul.icallv against all or part of the column of pulp in the container,

8, Means 'depending on the density of ore pulp in .a container for regulating the discharge of pulp therefrom, Said means lconsisting of a throttle valve or gate made in the form of a hollow cylinder` with thin walls, open at both ends and suspended from and integral with a float, the valve being at,- tached to the float with free communication between the inside of the valve andthe tioat being Sup, water balanced hypart of. the column the space above the pulp, ported on a column of draulically against all or of pulp in the container.

9`. Mea-ns dependingon the density of ore pulp in a container for regulating the discharge of the pulp therefrom, said means consisting of a throttle 'valve or gate made in the form of a cylindrical pipewith thin walls and open at both ends, suspended vertically from a float supported on a column of water balanced hydraulically against all or part of the columnof pulp in the conend. aca'eing arranged out-'-l a. float which .derives its support from be- "ingepartiallysubmerged in the liquid, the

inside of the valve having free communication With vthe `Space above the Surface of the liquid, the lower end of the valve coming into contact with a valve ASeat in the form of ,a frustum of a cone .with a hole through its axle, the valve Seat being of' euch a eine and position that contact between the valve and valve Seat takes place between the .inside edge of the flower' end pf the Vuelve and a circle of the conical surace.

1,1f A valve .for regulating the discharge of liquid from a container', the valve or moving portion being a. Straight cylindrical pipe/ina vertical or approximately vertical position, open at both ends, with its upper end open to the space above the surface of the liquid in the container and its lower end immersed in the'lquld7 a valve seat in the form of a frusturn of a rectangular cone with a hole through its axis, the axis of the cone being c oincident with the extension of the center line of the cylinder forming the valve, the motion of the valve being con-l -lined to a direction parallel withits center line, the small end of the fruetum being upward next the valve and smaller than the inside of thevalve, so that contact between the valve and `valve seattakes place when the valve is closed between the inner edge of the lower end of the valve and. acilcle of the conical surface.

12,` A valve for regulating the discharge of liquid from a containing vessel, the valve or In'oving part being a straight cylindrical pipe in a vertical or approximately vertical position, open at both ends with its upper end open to the space above the surface of the liquid in the container and its lower end immersed in the liquid, a valve seat in the forni nf the frustum of a rectangular cone with a hole through its axis., the axis of the cone being coincident with theextension of the center line of the cylinder vforming the valve, the motion of the valve being confined to a direction parallel with its center line, the small end of the frustum being upward next the valve and smaller than they inside of the valve seat takes place when thevalve isclosed between the inner edge of the lower endof the lvalve and a circle of the conical surface, the relative position ofthe Valve and valve seat depending on the buoyant force exerted on a body in the nature of a float either wholly or partially immersed in the liquid of the containing vessel.

13. In a hydraulic classifier, a teeter or pulp chamber wherein hindered settling conditions' are maintained, means for supplying unclassified pulp to --the teeter chainber and for conducting away the lighter portion of the pulp unable to sink into the chamber, means for regulating the discharge' of the heavy classified pulp from teeter chamber by a mechanical throttling valve in the form of a hollow cylinder open at both ends, and the operation of which is controlled by the changing ofthe density of the pulp 1n the teeter chamber, the valve seat of the throttling valve being in the shape of a rustum of a cone hollow through its axis.

14. In a hydraulic classier, a pulp or teeter chamber wherein hindered settling conditions are maintained, means for supplying unclassified pulp vto the chamber and for conducting away the lighter portion of the pulp unable to sink into the chamber, means for regulating the discharge ofthe heavy classified pulpfrom the teeter chamber by the use of a'mechanical throttling valve which is a hollow cylinder open at both ends and attached at its upper end to a fioat resting on a column ,--ofyvater balanced hydraulically against all -or part of the column'of pulp in the teeter chamber, the valve seat for the valveebeing in theshape of a frustum of a cone hollow through its axis. Y

15. In a hydraulic classifier, a pulp'or teeter chamber wherein hindered settling conditions are maintained, means for supplying unclassified pulp to the chamber and for conducting away the lighter portion of the pulp unable to sink into the chamber, means for regulating the discharge of the .heavy classified pulp from the lteeter chamber'bvv the use of a mechanical throttling valve hin the shape of a hollow cylinder open at both ends, its action depending on the use of a column of water balanced hydraulically against all or part of the column of pulp in the teeter chamber, and its seat being in the shape A.of a frustum of a cone hollow through its axis.

16. In Aa hydraulic classifier, a pulp or teeter chamber, means for supplying hydraulic Water to produce hindered settling classification therein, means for maintaining the even distribution of the hydraulic water over the teeter chamber area by forcing it to enter the teeter chamberA 'through numerous small openings distributed over,

the bottom of the teeter chamber, the said l openings being so lrestricted that they form enough resistance to the passage of the water that the 'distribution of the water is thereby maintained regardless of slight inequalities in vthe weight of the pulp bed at different points in the teeter chamber, means for supplying unclassified `pulp to the teeter chamberand for carrying away the overflow pulp made up of the particlesofjore too light to sink into the teeter chamber, `means for discharging the heavy classified portion of the pulp through a'restricted orifice at or near the bottom of the teeter chamber, with means for restricting the flow of the pulp at the point lwhere it leaves the teeter chamber by the use of a mechanical .valve or gate, the operation ofwhich-is accomplished by the use of a column of water balanced hydraulically against `all or part of the column of I pulp in the teeter chamber..

17'. In a hydraulic classifier, a pulp or teeter chamber, means for supplying hy draulic waterv to produce hindered settling classification therein, means for maintaining the even distribution of the hydraulic water overthe teeter chamber area by forcing it to enter the teeter chamber through numerous small openings distributed over the bottom the the teeterchamber, the said openings being so restricted thatithey form enough resistance to the passage of the water that the distribution of the water :is thereby maintained regardless of slight inequalities in the weight ofthe pulp bed at different 100 points in the teeter chamber, means for supplying unclassified pulp to the teeter chamber and for carryingaway the overflow pulp made up of the particles of ore too light to sink into the teeter chamber, means :for dism5 charging the heavy classified portion of the pulp through a restricted orifice at or near the bottom of the teeter chamber, means Jfor `regulating the outfiow of the 'heavy classi-l fied pulp from the. teeter chamber by the use of a throttling valve, the action of which is controlled by a float supported on a column of water balanced hydraulically .against all or part of the column of pulp in the teeter chamber.

v18. In a hydraulic classifier, a pulp vor teeter chamber, means for supplying Water to produce hindered settling classification therein, means for maintaining the even distribution of the Water over the teeter chamber area' by `forcing `it'lto enter the teeter chamber through numeroussmall openings distributed overI the bottom of the teeter chamber, the said openings being so restricted that they form enough resistance to the` passage of the Water that the distribution of the Water' kthereby maintained regardless of slight inequalities in the Weight of the pulp bed at different points in the teeter chamber, means for supplying un- Aand for regulating its rate of discharge by a throttling valve in the shape of a hollow i cylinder open at both ends and suspended from and integral with a float which is supported on a column of water balanced hydraulically against all or part of the columnv of pulp in the teeter chamber, the valve seat for the valve having an orifice through it for the passage of the pulp and beingof such a shape and size that when the valve is closed the -valve seat touches the valve only lat the inner edge of the lower end of the valve.

19. ln a hydraulic classiier, Aa pulp or teeter chamber, a hydraulic chamber beneath the teeter chamber'- and communicating therewith'by restricted openings, means for supn plyingwater to the hydraulic, chamber, a float chamber inside the classifier and supporting a column of'water balanced hydraulically against all or part of the. column of pulp in the teeter chamber, a stand pipe connecting with the hydraulic chamber and having an overflow above the float chamber and leading thereto, a throttling valve or gate for controlling the outflow of the heavyclassiiedpulp Jfrom the-teeter chamber, the said valve-being operated by a float in the oat chamber.

20. ln a hydraulic classifier, a pulp or teeter chamber, a hydraulic chamber beneath the teeter chamber and separated therefromv by a partition having highly restricted openings, means for supplying water to the teeter chamber through the hydraulic chamber and the restricted openings in such quantity that the pressure head maintained across the partition will give even distribution ol the water to the' restricted openings and hence to allv parts of the teeter chamber, a float` chamber inside of the classifier and containing a column of Water balanced hydraulically against all or part of the column of pulp in the teeter chamber, a stand pipe in connection with the hydraulic chamber and having an overflow above the float chamber and leading into the float chamber, 'a tloat in the doat chamberconnected with and operu ating a mechanical device which regulates the outflow of the heavy classified pulp from,

the teeter chamber.

21., ll'n a hydraulic classifier, a pulp or tester chamber, in 4all parts of which `a uniform hindered settling bed ot pulp is maintained by hydraulic water entering the teetcr chamber through numerous small openings in the bottom thereof and under suicient pressure to overcome slight inequalitiesy at different points in the pulp bed, a float chamber supporting a column ol water bal ramper anced hydraulically against all or partv ofA the column of pulp in the teeter chamber, means controlled bythe density of the pulp in the pulp bed for supplying water to the top of the float chamber, a iioat inthe float I chamber, and a mechanical device operated by the float for regulating the outilow of the geavy classified pulp -from the teeter chamN 22. ln a device of the character specified, the combination of ateeter chamber, a feed water chamber 'located above the teeter chamber, means-for maintaining a constant depth of water in the feed water chamber, and a valve or'gate controlled by the density of the pulp bed and balanced hydraulically against the pulp for regulating the discharge of the heavy classified pulp from the ing the discharge of the pulp from vthe teeter chamber.

2l. ln a device of the character described, a teeter chamber, a hydraulic chamber there beneath and separated therefrom by a partition through which highly restricted openings are formed, means for supplying water, throu h the partition to the teeter chamber in suc a quantity that a` predetermined pressure head may be maintained acrossl the partition to ell'ect even distribution of the Water to all parts oi the teeter chamber, and means depending on the use of a column of Water balanced hydraulically against a column ot' the liquid ore pulp in the teeterchamber for regulating the discharge of the pulp from the teeter chamber.

25. lln a device or the character specied, a teeter chamber, means lor supplying water to the teeter chamber and means for restricting Vthe dow oit the water as it enters the teeter chamber insuch a manner as to maintain its even distribution over the teeter chamber area, and means depending on the use of a column of water balanced hydraulically against a column of the liquid ore pulp in the teeter chamber for regulating the discharge ont the pulp from the teeter chamber, 26. ln a' device of the character specified, a teeter chamber, means for supplying water to produce hindered "settling classification therein, means for maintaining the Aeven distribution of the water over ythe teeter chamber area by forcing it to enter the teeter Mld chamber 'through numerous-'small openings distributed over the bottom of the Ateeter chamber, the said openings being yso restricted that they form enough resistance to the' passage of the water that. the distribution of the water is thereby maintained regardless o slightinequalities' in the weight of the pulp bed at different points in the teeter chamber, and means depend-ing on the use of a column of water balanced hydraulically against the .teeter chamber for regulating the' dischageof the pulp-from the teeter chamber.

the pulp unable vto smk into theteeter cham-v ber,

a columnof the liquid ore pulp -in I hydraulic classiier,'a\ .pulp orA teeter chamber wherein hindered settling conditions are maintained, means for sup- `means for regulating the' discharge of the heavy classiied portion of.` the `pulp, from the teeter chamber by a throttling Valve-in the shape of a hollow cylinder Awith thin walls, the operation of which depends on the use of a column of water balanced hydraulif cally against` all or part of the column of pulp. in the teeter chamber. A

28. As a means of regulating'the discharge ore pulp from a containing vessel, the use, in combination, of a 4valve in theI shape of a hollow cylinder with thin `walls and al column of water balanced hydraulically against a column ofthe ore pulp in the containing vessel ROBERT BAXTER ELDER.- -Witnesseszl 1 AmnRNoN S. LONG,I Mmmm E. WmoN. 

